Numerical study on a hydrogen-fueled rotary engine with jet-diffusion combustion driven by a novel pre-chamber

To address leakage and backfire problems of Hydrogen-fueled Wankel rotary engines (HWREs), a novel pre-chamber (PC) was proposed in this study. For the proposed novel PC, all of the hydrogen is supplied in the PC and is ignited during injection to achieve diffusion combustion. The numerical simulation was conducted to investigate the effect of jet nozzle angles (JNA) and hydrogen injection timings (HIT) in this study. The results show that a larger JNA can enhance gas exchange within the PC. The best power and efficiency of the HWRE is achieved when a JNA of 60° with the HIT at 40 °CA BTDC. In this setting, the indicated thermal efficiency and indicated mean effective pressure reach 33.9 % and 0.66 MPa, and the mass of unburned hydrogen is reduced to 0.94 %. Moreover, NOx emissions increase as the region area and duration are higher in the high-temperature zone of the cylinder. Besides, a JNA of 45° with HIT at 75 °CA BTDC can also achieve slightly higher power. However, under this strategy, the area of the high-temperature region and the duration of the high-temperature is increased, which causes ultra-high emissions.